I made a model too tall, how do I chop the bottom part off?
This is probably not the most efficient way, but it's simple and clean.


I hit z to enter wireframe mode.
Then NumPad_1 to enter front view mode (depending on how your
boat is orientated, it could be NumPad 3, side view)
Then b to box select the bottom faces (one row before the
vertices you want to keeP)
Then x and Delete Vertices
Making sure I had the vertex select mode on, I clicked one
vertex away from the corner, held CTRL and right clicked the
point opposite it which was one vertex away from the opposite
corner. (Holding control while right-clicking selects the shortest
path between selections). I do the same for the other side of the
boat.
Then Space and type in Bridge Edge Loops
I hit CTRL + r to enter loop cut mode and hover my cursor over the newly made row of planks and type in the number of loop cuts I want to be made. I made it 2 because I had 2 middle vertices I needed to be joined with something. Then once the pink lines are where you want, hit Enter twice.
Finally, use b to box select, c to circle select, or simply
right-click the vertices left and hit f to join them into faces.
Do this by sets of 4, not all at once.




Or, try selecting the hole's perimeter with Alt + Right Click then hitting Space and typing in Grid Fill. Sometimes that works, and sometimes it doesn't.